The objective of this report is to show the efficacy of amprolium to prevent gastroenteritis due to Cystoisospora in infected kennels.

Amprolium hydrochloride is 1-[(4-amino-2propyl-5-pirimidinyl)methyl)]-2-methylpyiridinium -chloride], thiamine analogue and is a competitive antagonist of thiamine transport mechanisms. This drug exhibits coccidiostatic activity and reduction of oocyst discharge.

In the infected kennels Isosporaof the I. ohioensis group were isolated.

113 pups of different breeds (German Sheppard, Boxer, Rottweiler, Beagle, Samoyed and Keeshond) between 23 to 120 days of age were treated with amprolium, and 50 pups of the same breeds already mentioned (control group) received sulfas. The pups were allocated in the kennel facilities (cages) and received the drug when they started to be fed, during 10 days, rested for 7 days and reinitiated the treatment. Control pups received treatment when the owners saw symptoms of the disease. The dose of amprolium was 150mg/kg given in tablets. Samples of faeces were taken previously to the administration of the treatment and during the trial, every week, and studied by flotation Sheather' s technique. The puppy's weight was measured every week and the firmness of the stools was observed every day and classified ( liquid, flabby, semisolid, solid)

The Fisher exact Test and kappa coefficient were used for the statistical analysis of data, no significant differences were observed between amprolium and sulfonamides on the shedding of oocysts. The weight gain (for each breed) showed significant differences, positive for the amprolium group. Significant differences were also observed in the firmness of the stools: in the amprolium group faeces were always solid after the intake of the drug.

It is concluded that amprolium is a useful drug for the preventative treatment of coccidiosis in infected kennels.